The present invention relates to an elongated apparatus for aerating water with fine and large bubbles. The apparatus has a support body, that extends essentially over the length of the apparatus, for a hose-like sleeve that tightly surrounds the support body and is made of rubber, or rubber-like materials. The sleeve is provided with a large number of slits that are distributed over the periphery of the sleeve and that open under the effect of compressed air.
With the heretofore known apparatus of this type, the support body is a tube, the hollow space of which can be flooded to avoid an undesirable buoyancy. When such an apparatus is supplied with compressed air, there is formed between the support body and the sleeve a region that is filled with the compressed air and that has a circular cross-sectional configuration that on the whole has a relatively great frictional resistance for the air and hence results in a correspondingly great loss of pressure. In addition, these known apparatus have the danger that the air bubbles that are discharged from the lower slits combine to form large bubbles. This adversely affects the aeration.
It is therefore an object of the present invention to eliminate these drawbacks, or at least to considerably reduce the effect thereof.